1. Field of the Invention
The present invention relates to a marking device.
Within the scope of the invention, the generic term "marking device" designates any device for making a pattern on the surface of a piece, whether by printing, deformation or removal of matter at the level of this surface.
2. Brief Discussion of the Related Art
A marking device comprises, in known manner, a framework supporting a mechanism for driving a marking tool, which may be a pneumatic stylus or an engraving head. Such a drive mechanism conventionally comprises an element fixed with respect to the framework, provided with raised edges on which are disposed two guide bars. A first carriage is mounted to slide on said bars and is itself provided with two additional bars, perpendicular to the first couple of bars and which are intended for receiving a second carriage to which the marking tool is fastened.
Thanks to the use of this so-called "crossed carriage" system, the marking tool is adapted to move in two directions perpendicular to each other, with respect to the fixed element.
However, such a marking device has certain drawbacks. In effect, the high number of its constituent elements leads to the existence of considerable functional clearances. Moreover, the rigidity of these constituent elements is relatively slight, due to their lightness, with the result that they are sometimes subjected, in service, to certain deformations. Finally, such a marking device sometimes employs synchronous belts for driving the carriages, inducing a phenomenon of elastic deformation. All these characteristics therefore results in a certain lack of precision in the positioning of the marking tool thus produced.
Moreover, the different constituent elements of the marking device are subjected to considerable frictions, with the result that the mechnanical output of this device is not optimum.
In order to overcome the drawbacks of the prior art set forth hereinabove, the invention proposes producing a marking device which, while being sufficiently light, guarantees a precise positioning of the marking tool and is subjected, in service, to slight frictions.